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JANUARY 2008 UCCS STANDARDS 15950-28
I. Refrigerant Vapor Sensor: Analyzer shall be microprocessor-based and employ infrared
(lR) sensor technology, to provide sensing down to one (1) part per million (ppm) and shall
be chemical-compound-specific and calibrated for either refrigerant R-11, R-12, R-22, R-
123, R-134a, or other refrigerant as required by the chiller system. Any installed unit can be
switched to monitor, at a future date, another refrigerant type by replacing one component
and recalibrating (i.e. R-11 to R-123, etc.). Initial alarm output setting shall comply with
recommended Allowable Exposure Level (AEL). Adjustable, three (3)-level alarm for each
point, shall be supplied with common alarm output contacts. Provide local digital indication
of refrigerant concentration in ppm (microprocessor shall identify sample point and ppm of
alarm by flashing display.) Unit shall have self-diagnostics, and supply contacts for a
common malfunction output. Loss of sample flow at either sample or ZERO line shall
indicate system malfunction.
Unit shall have a sensitivity of 1 ppm, resolution of 1 ppm, noise rating less than .5 ppm,
and drift less than .5 ppm to the calibrated refrigerant.
The unit shall be enclosed in a NEMA-4, metal, wall-mount enclosure. Auto-zero calibra-
tion shall be initiated at one hour intervals (factory set), or manually at the monitor, and
shall be accomplished by drawing air from an uncontaminated air source. Include built-in
sample pump and differential pressure flow switch for low-flow indication. Provide 4-20
mA dc analog output of refrigerant level for input into Direct Digital Control (DDC) or
Building Management System (ABMS). Unit shall be insensitive to vibration, temperature
variations, and shall have a provision for continuous sampling. Intermittent dump and
purge, and batch-type sampling with long response times shall not be acceptable. Response
time shall be twenty (20) seconds. Malfunction relay is energized due to flow loss or
electrical malfunction.
The system shall be provided with a relay board, with dry contacts for each channel, to
initiate output signals for three (3) concentration-level alarms at the local panel, the inter-
face to the DDC or BMS, and the building ventilation system. Alarm levels will be pro-
vided at the TLV-TWA levels of - 1st Level, 200 ppm; 2nd Level, 300 ppm; 3rd Level 500
ppm. The third level shall activate the warning horns and ventilation fans. Provide dry
alarm contacts for each alarm level for interface to the DDC and Fire Alarm System.
Unit must be factory calibrated. No field calibration is acceptable at time of installation.
Maintenance & Calibration: No calibration shall be required for a period of one (1) year
from date of shipment. Zero-filter and end-of-line filters should be replaced every three (3)
to six (6) months or sooner, based on usage. Provide four (4) extra filters of each type.
2.13 ACTUATORS - ELECTRIC
A. Electric actuators are acceptable. HVAC Shop will pre-approve.
B. Actuator size and rating shall be suitable for intended application.
1. Damper actuators shall be selected per manufacturer's recommendations to provide
sufficient close-off force to effectively seal damper. Modulating actuators shall